








key: cord-277640-vy7ex5lv
authors: Calderaro, Adriana; Arcangeletti, Maria Cristina; De Conto, Flora; Buttrini, Mirko; Montagna, Paolo; Montecchini, Sara; Ferraglia, Francesca; Pinardi, Federica; Chezzi, Carlo
title: SARS-CoV-2 infection diagnosed only by cell culture isolation before the local outbreak in an Italian seven-week-old suckling baby
date: 2020-05-14
journal: Int J Infect Dis
DOI: 10.1016/j.ijid.2020.05.035
sha: 
doc_id: 277640
cord_uid: vy7ex5lv

SARS-CoV-2 is emerged in China on December 2019 and now declared pandemic by WHO. We describe the case of an Italian 7-week-old suckling baby SARS-CoV-2-positive only by cell culture method with no clinical suspicion and/or risk factors of SARS-CoV-2 infection. The patient was referred to the hospital with signs and symptoms of infection of the upper respiratory tract before the virus was spread to the province. Nasal and pharyngeal swabs and a nasopharyngeal aspirate were used for conventional and molecular diagnostic assays not including SARS-CoV-2 virus. Bacteria referred to resident population were revealed in nasal and pharyngeal swabs. No viruses were detected using both immunofluorescence assay and nucleic acid amplification assays in the nasopharyngeal aspirate. The baby was discharged in good conditions after 3 days of hospitalization. Later a cytopathic effect on the cell monolayers currently used for respiratory viruses was observed and the viral particles were identified as Coronaviridae by transmission electron microscopy. SARS-CoV-2 was identified by RT-PCR performed both on cell culture and on the stored aliquot of the original sample. The virus isolate was named SARS-Cov-2/human/Parma/1/2020.Cell culture still remains the only reference diagnostic method also for emerging viruses, allowing to reveal cytopathogenic viruses and demonstrating their infectivity.

A novel coronavirus was initially detected in Wuhan (China) starting from December 2019 in patients with severe pneumonia of unknown origin (Chen and Yu, 2020) . Genome sequencing allowed to classify the virus into the subgenus Sar-becovirus of the genus Betacoronavirus; it was termed as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the illness it causes as coronavirus disease 2019 (COVID-19). On March 11, 2020 the World Health Organization declared SARS-CoV-2 pandemic, considering the over 118,000 cases of the coronavirus illness in over 110 countries around the world (World Health Organization, 2020). The first case of SARS-CoV-2 infection in Northern Italy was assessed on 7 February, 2020 in a Chinese subject recently returned from Wuhan, but the infection has become epidemic in Northern Italy since February 21, 2020, when autochthonous cases have been identified (Spiteri et al., 2020) . At the date of manuscript submission, Italy was the second country with the highest number of SARS-Cov-2-infected subjects after USA (Ministero della Salute, 2020).

In the area of Parma, where our laboratory is located, SARS-CoV-2 became epidemic on March 3, 2020, and has reached 2083 cases on April 3, 2020.

Older age and comorbidities were associated with more severe clinical pictures, while the clinical course was generally milder in young subjects. Available data regarding the clinical symptoms of the infection were mostly obtained from the elderly or subjects aged > 18 years old (Salehi et al., 2020 , Huang et al., 2020 . To the best of our knowledge, no literature evidence of SARS-CoV-2 virus infection diagnosed including virus isolation is present for suckling babies and very little evidence for new-borns (Lu and Shi, 2020, Wang et al., 2020); in these reported cases, laboratory diagnosis was only done by molecular methods.

Here we describe the case of a seven-weekold suckling baby infected by of SARS-CoV-2 virus presenting fever and polypnea.

The patient was referred to the Neonatology ward of the University Hospital of Parma (Italy) in the night of Only the culture isolation of this cytopathogenic agent allowed its final identification as SARS-CoV-2.

Indeed, the clinical characteristics of the case and the time period in which the little patient came to the medical observation did not allow to suspect this specific infection, making it unnecessary to submit the baby to chest radiographs and CT scan; the baby has been discharged from the hospital in good conditions on February 28, 2020, and remained healthy in the following weeks. Pharingeal swabs at 2 consecutive days were performed by the Public Service of Health, 2 weeks after his discharging from the hospital, and both resulted negative for SARS-CoV-2 RNA.

The origin of the infection of the baby remains not clear; in the period before the admission to the hospital the parents were healthy, although the mother declared a slight malaise didn't stop her from breastfeeding They have never been tested for SARS-CoV-2 because they resulted healthy until March 17, 2020.

However, after the baby was discharged, they remained at home in self-isolation, together with the baby.

To the best of our knowledge, in the international literature at the time of the manuscript submission, no other reports of infants of this age describing the laboratory diagnosis of SARS-CoV-2 infection including virus isolation together with RNA detection were present.

The presented results highlight the importance of viral culture, to be used in parallel to molecular techniques, being the only reference laboratory method able to reveal the presence of cytopathogenic viral agents and demonstrating their infectivity also in case of emerging viruses. This is of relevance in those cases, such as the one described here, in which the symptoms are mild and the laboratory becomes an essential support to promptly report the presence of this pandemic virus for preventing its spread. This result stimulates not to limit the diagnosis to molecular tools in all the 

This study was supported by the Ministry of University and Scientific Research Grant FIL, Parma. Italy

The samples analysed in this study were sent to the University Hospital of Parma for routine diagnostic purposes, and the laboratory diagnosis results were reported in the medical records of the patients as answer to a clinical suspicion; ethical approval at the University Hospital of Parma is required only in cases in which the clinical samples are to be used for applications other than diagnosis. 

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The authors declare no competing interests.

☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

